Ultrasound/contrast imaging is commonly performed by a clinician using a hand held probe which is positioned adjacent to a patient. However, the effective use of a hand held probe is limited by frame-to-frame variability in the images produced, occupational health hazards, and the inability to monitor an organ of interest during exercise induced stress. These limitations can seriously and deleteriously affect the utility of the ultrasound/contrast imaging technique.
Frame-to-frame variability in the images arises from movement of the probe between successive images. To minimize distortions resulting from frame-to-frame variability, the probe must be maintained in a steady orientation relative to the patient. For example, when imaging a patient's heart, 5 to 10 cardiac cycles are typically needed for contrast myocardial perfusion to occur before the next ultrasound wave is emitted. Since a cardiac cycle is typically about 1 second in duration, a clinician must be able to steadily hold a probe for 5 to 10 seconds between successive ultrasonic emissions. Movement of the probe during that time period will result in frame-to-frame variability between images and cardiac views obtained.
Additionally, holding the probe in a steady orientation for long periods of time can lead to occupational health hazards (e.g. ergonomic injuries). Mercer et al., J. Am. Soc. of Echocardiography, pp. 363-366 (May 1997), reported studies relating to the occupational health hazards due to long term use of hand held probes. The hazards include muscle strain and injury from standing over the patient, carpel tunnel syndrome resulting from wrist strain, stress and burnout due to long days of repetitious probe holding, and an increased likelihood of disease transmission between the patient and sonographer.
Further, it is impractical to use a hand held probe to monitor the organ of interest while the patient is undergoing exercise-induced stress. As a result, ultrasound imaging with stress exercise is traditionally performed only before and after the stress is performed. However, it would be beneficial to monitor ultrasound images while the patient is actually undergoing exercise-induced stress.
In light of the foregoing, it would be beneficial to provide an apparatus and a method for hands-free use of an ultrasonic probe to monitor an organ of interest. The apparatus and method should enable the orientation of the probe to be adjusted relative to the patient in order to produce optimal images of the organ of interest. However, once the position of the probe has been adjusted, the apparatus and method should enable the probe to be maintained in that position throughout the ultrasound procedure, in order to minimize the effects of frame-to-frame variability in the images. Further, the apparatus and method should reduce the incidence of occupational health hazards associated with the long term use of hand held probes and enable images of the organ of interest to be produced while the patient is undergoing exercise-induced stress. Additionally, the apparatus and method should be adaptable to work in cooperation with the known hand held ultrasonic probes.